package gogohome.ourhome;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class aes_clint {
	 public static String encrypt(byte[] rawKey, String cleartext) throws Exception   
	 {   
	  //byte[] rawKey = getRawKey(seed.getBytes());   
	  byte[] result = encrypt(rawKey, cleartext.getBytes());   
	  return toHex(result);   
	  }   
	   
	   
	  public static String decrypt(byte[] rawKey, String encrypted) throws Exception   
	 {   
	  //byte[] rawKey = getRawKey(seed.getBytes());   
	  byte[] enc = toByte(encrypted);   
	  byte[] result = decrypt(rawKey, enc);   
	  return new String(result);   
	  }   
	   
	   
	  public static byte[] getRawKey(byte[] seed) throws Exception   
	 {   
	  KeyGenerator kgen = KeyGenerator.getInstance("AES");   
	  SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");   
	  sr.setSeed(seed);   
	  //kgen.init(128, sr);   
	  kgen.init(64, sr);
	 // 192 and 256 bits may not be available   
	   
	   
	  SecretKey skey = kgen.generateKey();   
	  byte[] raw = skey.getEncoded();   
	  return raw;   
	  }   
	   
	   
	  private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception   
	 {   
	  SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");   
	  Cipher cipher = Cipher.getInstance("AES");   
	  cipher.init(Cipher.ENCRYPT_MODE, skeySpec);   
	  byte[] encrypted = cipher.doFinal(clear);   
	  return encrypted;   
	  }   
	   
	   
	  private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception   
	 {   
	  SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");   
	  Cipher cipher = Cipher.getInstance("AES");   
	  cipher.init(Cipher.DECRYPT_MODE, skeySpec);   
	  byte[] decrypted = cipher.doFinal(encrypted);   
	  return decrypted;   
	  }   
	   
	   
	  public static String toHex(String txt)   
	 {   
	  return toHex(txt.getBytes());   
	  }   
	   
	   
	  public static String fromHex(String hex)   
	 {   
	  return new String(toByte(hex));   
	  }   
	   
	   
	  public static byte[] toByte(String hexString)   
	 {   
	  int len = hexString.length()/2;   
	  byte[] result = new byte[len];   
	   
	   
	  for (int i = 0; i < len; i++) result[i] =    
	 Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();   
	  return result;   
	  }   
	   
	   
	  public static String toHex(byte[] buf)   
	 {   
	  if (buf == null) return "";   
	  StringBuffer result = new StringBuffer(2*buf.length);   
	   
	   
	  for (int i = 0; i < buf.length; i++)   
	 {   
	  appendHex(result, buf[i]);   
	  }   
	   
	   
	  return result.toString();   
	  }   
	   
	   
	  private final static String HEX = "0123456789ABCDEF";   
	   
	   
	 private static void appendHex(StringBuffer sb, byte b)   
	 {   
	  sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));   
	  }   
	 
}
